In addition MoI does not have dimensions and line weights yet. I use MoI most days for architectural design modeling and to some extent 2d working drawings but then have to switch to Rhino for completing drawings and renderings. It is a pretty smooth workflow between those two.
I almost never use SketchUP though I did some in it's very early days. It does not flow for me easily ... probably because I don't use it enough to be adept with it.
cheers,
eric